| In this thesis, The tides and tidal currents in the seas adjacent to Zhejiang Province are simulated with a three-dimensional baroclinic primitive equation model-Hamburg Shelf Ocean Model(HAMSOM). Two numerical techniques-nested grid and moving boundary method are used successfully and high precision results which compared with the observed ones are obtained. These results reveal the characteristics and the moving rules of the tides and tidal currents in this area.Based on the materials observed many years at the tidal observatories and the ocean current data measured in the coastal zone and islands in Zhejiang Province, the characteristics of tides, tidal currents and residual currents are analyzed and processed by harmonic analysis and statistical methods systematically. Such research results are compared with those from the numerical simulation to validate the effectiveness of the latter.Because of the flexuous coastal line and the diverse topography of Zhejiang Province, nested grid method is used to simulate the interested research area with fine grids of 1'×1', and analyses the whole area of Bohai Sea, Yellow Sea and East China Sea, including the seas adjacent to Zhejiang, with wide grids of 10'×10'. The opening boundary condition of the small area is obtained from the calculation results in large area. Furthermore, according to the feature of widely distributed intertidal regime along the coast, moving boundary method is used to truly simulate the water area with such changes. The original HAMSOM model is improved by two numerical methods proposed in this thesis, and is applied to simulate the tides and tidal currents in the seas adjacent to Zhejiang, which is proved to be effective. Comparing the computed values with those of 50 tidal observatories, we find that the computational precision with fine grids and moving boundary are generally higher than that with wide grids or fixed boundary. The root-mean-square values of the comparative results show that the difference between the simulated and the observed amplitudes of M2 constituent is only 4.6cm, the difference of phase-lags is 7.1 ; the difference of amplitudes and phase-lags of S2 constituent are 5.0cm and 5.4 ; the difference of amplitudes and phase-lags of K1 constituent are 2.3cm and 5.8 ; the difference of amplitudes and phase-lags of O1 constituent are 1.6cm and 5.5 .In addition, we choose 105 current stations, and compare between the calculated and observed harmonic constant, U cos , U sin , V cos , V sin of M2 and K1 component currents at surface layer, and the results also indicate that the computational results agree with observed ones well.After validating the good agreement between simulated results and observed ones,The characteristics and the distribution rules of tides and tidal currents in the whole seas near to Zhejiang are thoroughly analyzed, mainly based on the simulated results, combining with the observed conclusion. The co-tidal and co-range charts, co-current charts, types of tides and tidal currents, distribution of maximum possible tidal range and maximum possible tidal current, phenomenon of diurnal inequality, moving modes of tidal currents, tidal ellipses, distribution of tidal residual currents and the vertical structure of tidal currents and residual currents are investigated respectively. And thereout we draw a series of meaningful conclusions as follows, the main of these are:1. Semi-diurnal constituent is the dominant component tides in this area. The co-tidal and co-range charts show that neither semi-diurnal constituents nor diurnal constituents have tide-free points. Only the shallow constituents M4 and MS4 respectively have three and two tide-free points. The co-current charts of main constituents show that the M2 component currents have one current-amphidromic point at 29° 18'N, 122° 46'E, and the co-phase lag lines rotate anti-clockwise here. The K1 component currents have no current-amphidromic points in the whole area.2. In this area, the type of tides an...
|
PDF Full Text Request